1. Field of the Invention
The present invention relates to a solid-state imaging device and a manufacturing method thereof, and is applied, for example, to a MOS solid-state imaging device.
2. Description of the Related Art
At present, solid-state imaging devices including CMOS sensor are applied to various uses, such as digital still cameras, video movie cameras and monitor cameras. In particular, dominant devices are single-chip imaging devices which acquire plural color information by a single pixel array.
With a demand for an increase in the number of pixels and a decrease in optical size in recent years, there is a tendency that the pixel size is reduced more and more. For example, the pixel size of a CMOS sensor which has widely been used in recent years in digital cameras or the like is about 1.4 μm to about 2.8 μm.
As a structure for coping with such fine pixels, there is known, for instance, a back-surface illumination type solid-state imaging device (see, e.g. Jpn. Pat. Appln. KOKAI Publication No. 2006-128392). In the back-surface illumination type solid-state imaging device, incident light is radiated on a silicon (Si) surface (back surface) which is opposite to the silicon (Si) surface (front surface) on which a signal scanning circuit and its wiring layer are formed. In this back-surface illumination type structure in which light is incident on the silicon (Si) surface which is opposite to the silicon (Si) surface on which the signal scanning circuit and its wiring layer are formed, the light, which is incident on the pixel, can reach a light-receiving region, which is formed within the silicon (Si) substrate, without being blocked by the wiring layer. Thus, even with the fine pixel, a high quantum efficiency can be realized.